AutoblogGreen

After Bob Lutz made the announcement about the deal to work with A123 Systems on the cells for the Chevy Volt battery packs to be supplied by Continental, AutoblogGreen sat down to chat with GM's battery chief Denise Grey. Denise is responsible for the battery development work on all of GM's hybrid and electric programs.

AutoblogGreen: I'm here with Denise Grey who is the director of Energy Storage Systems at General Motors and you're in charge of all the battery development for hybrids and electric vehicles?

Denise Grey: That's right.

ABG: Why don't we start off by talking a little bit about the announcement that Bob Lutz made this morning about A123 Systems and GM.

DG: Okay. To put it in perspective, we've got two contracts that we announced back in the May timeframe for the Chevy Volt E-Flex System; one was LG Chem with Compact Power. Compact Power's a subsidiary of LG Chem, and that in essence covers the cells as well as the pack. The other thing in May we announced Continental which is our pack supplier. Today's announcement kind of completes the four quadrants for the cells – A123 will be providing cells to Conti for their particular system, so in essence we complete the four-piece partnership. A123 brings that nano-phosphate technology, their lithium ion chemistry to the forefront and by working with them we can understand specifically how that chemistry works, how do we create the battery state estimation protocol so that we can in essence control that system effectively. We're already doing that with Compact Power and now this gives us that additional insight from a nano-phosphate lithium ion perspective.

Continue reading Denise Grey's answers after the jump.ABG: So basically the change in what you're doing with A123 is working more closely with them to better understand how the battery works?

DG: Yes.

ABG: And managing that?

DG: In both ways. They get a chance to get a feel firsthand how the automotive supplier's going to actually ultimately use it, and then we also get a chance to understand how their nano-phosphate technology works so that we can again understand it appropriately so that we can use it effectively.

ABG: Does this impact Compact Power in any way?

DG: Equal opportunity here. My overall goal is that both end up with technologies that can meet all our ultimate needs. So Compact Power and Conti A123 have equal opportunity, equal chance to be in our Chevy Volt.



ABG: As far as the development so far on the Volt and the E‑Flex architecture, how's that proceeding? Where's GM at with that right now?

DG: The plan we have is pretty much a year contract to develop the requirements to produce cells, to produce packs for our bench testing, and ultimately produce packs for our vehicle work. We've got that plan in place. We're starting to go through those various deliverables and, quite frankly, my confidence hasn't decreased in the, the number of months that we've been working on it so far. We've got a good chance of making this thing work, but we've got a lot of work to do in the meantime to get the data that goes beyond the simulation, the analysis, to really get the real data to prove that those stimulations and analyses were correct. So we're at the very beginning of that process and within this year, we'll be able to have some really good feel if we can meet our overall goals.

ABG: What kind of time-line does GM have for having some running prototypes with prototype lithium packs in them?

DG: We're hoping by next spring, the spring of 2008, we'll be able to have some packs with our early development vehicles, early prototypes of our particular E-Flex Volt system.

ABG: Getting away from the E-Flex for a moment, let's talk about the plug-in Vue program which is also using lithium ion packs and A123 is one of the suppliers on that program. How's that program proceeding?

DG: We're doing pretty good. Those contacts were announced in the early January timeframe, and again Johnson Controls/Saft and Cobasys with A123. We've already received samples of the actual cells and the cells have been going through numbers of iterative design changes in order to really zoom in on the ultimate requirements. So that's progressing pretty good. We will be receiving some packs shortly from the suppliers that we can then put in our laboratory from a pack perspective, because we already have them in our labs from a cell perspective. We'll be able to put them in our labs from a pack perspective to begin getting some integration learnings, cooling system, electronic systems, the batty management system, as well as being able to cycle these things to and fro. Additionally because it's a plug-in, we've got charger work that we have to do and there's communications between the charger, the battery pack, the vehicle systems controls, and we'll be able to do some of that work on our bench as well. So it's progressing as well, as we probably got a five-month lead time ahead of a Chevy Volt as far as deliverables, but again it's making progress, making a lot of progress.

ABG: When Rick Wagoner initially announced that program last November at LA, he talked about 2009 timeframe for delivery of that vehicle? Is that still the target?

DG: Well, I'm not quite sure of the ultimate timing. I think a lot of it's gonna be a function of how we progress for the battery. I know that timeframe and other timeframes have been talked about. But it's really going to be a function of the progress we make on these lithium ion batteries to meet all of our ultimate requirements from a power-energy perspective, from a life and being able to cycle them, being able to cool them down effectively to make sure that we can meet all of our overall program needs.

ABG: As far as the suppliers that you've chosen and some of the other suppliers that are out there, can we talk a little bit about the process that GM went through in deciding which suppliers to work with and what your criteria were?

DG: There were probably a list of 10 or 12 approximately attributes that we were evaluating each supplier on. It ranged from their power energy density. It ranged from their ability to package, to design cells in a pack that fits in the Two-mode Saturn Vue packaging activity location, and I guess that's for the Two-mode but also the same thing for the E-Flex, the packaging of the physical integration requirements. We talked about thermal. We've got to make sure that from a Chevy Volt perspective that with the condensed packaging that we've got there that we can cool these batteries, not just from the energy, to predict the energy that the batteries create, but also based on the packaging configuration we have and the air flow, we got to make sure that they've got a credible design from a cooling strategy perspective. Electronics – there's a lot of voltage, currents, temperature sensing, cell balancing, communications with the rest of the vehicle, diagnosability, all of that electronic design has to be created; and so that was a part of our evaluation, and then last but not least amongst the criteria is timing. This program is extremely aggressive. We've got some huge timing constraints on us and so we needed to evaluate the ability of the supplier to, to provide cells, to provide packs for bench testing, for vehicle testing per our requirements; and so that amongst other requirements – we went through and we weighted all of those different parameters, went through an analysis to determine which ones would end faring out as the most profitable, most probable to come up with a design, and for the Chevy Volt that is CPI/LG Chem, as well as Continental A123 combination were those who stood out.

ABG: Another subject that comes up from the readers of AutoblogGreen regularly is the idea of battery leasing and also battery exchange programs as an alternative to fast-charging batteries in a vehicle. Can you talk a little bit about those?

DG: Yeah, I think those are excellent concepts, excellent things for us to think about. We've got, when it comes to battery life and use after useful vehicle life, there's a number of different means. These are energy storage devices that can be used for a number of different things and interchangeability and how do we somehow stretch its life or stretch its usefulness is, I think, extremely important. So all of those kind of things, leasing, interchangeability, I think all of those are amongst the subset of possibilities that we will be, we have been and we will continue to explore as possibilities.

ABG: Is there anything else you would like to add?

DG: I guess, as a last point, I just think GM, our ability to put the Chevy Volt into production is going to be a function of getting the right suppliers on board, the right suppliers with the right attitude of innovativeness, of working very closely with the OEMs and the OEMs working very closely with the suppliers and really understanding the technology and really exploiting it in an optimized way from a vehicle perspective, and so I think the suppliers that we named today, maybe the suppliers we'll name tomorrow, that's what we're ultimately looking for; those who will be with GM in general and kind of co-develop these technologies 'cause it's gonna take all of us in order to try to bring all of this to fruition.

ABG: Well, thank you very much.

Postscript: This was actually the second pass at the interview with Denise Grey. A technical issue with my recording gear messed up the first attempt. In our first conversation we touched on a couple of other issues that we didn't hit this time due to time constraints. We talked more about interchangability of batteries which would allow drivers to pull into a service station and swap out a battery pack instead of waiting for a charge.

There are a number of issues with this. First of all because of the size of battery packs using common form factors would put more packaging constraints on car companies as far as design. More important is the issue of safety. Electrically driven vehicles have very high voltage circuits and the handling of the connections can be very dangerous. Constantly plugging and unplugging these connections would cause a lot of wear and tear issues which would greatly reduce reliability and safety.

Finally we also discussed the idea of using off the shelf cells and assembling their own packs the way Tesla does. Denise said GM has not ruled that idea out but at this time it's not really practical or cost effective. Using thousands of smaller cells makes assembly much more complex and expensive. Nonetheless it's an area that GM has looked at and will continue to examine.